Can you explain how the test.client service definition is related to phpunit configuration in phpstorm? What exactly did you had to do besides installing browser-kit?

I think the error can also occur when the test client isn't enabled in the framework bundle config.

Had this issue too, when I ran the command: composer dump-env test it was fixed.
When framework.test is not true, the test.client service gets removed from the container.

Does someone want to create a PR also including the framework.test config option in the error message?

Ok, couldn't reproduce this on a clean install anymore but went back to our original project.
I understand totally what happens..

Our application runs in a docker container where we have set up environment variables on machine base, and because it is on machine base the DotEnv component did not overwrite it with the value of phpunit.xml.dist

Because now our application is running under dev environment, the FrameworkExtension did not load the test.xml which contains the service definition of test.client.

Do we want to throw another exception that tests should be ran under APP_ENV=test or just add that framework.test should be set on true? Wdyt @xabbuh

the message should talk about the framework.test config setting. The fact that there is an environment named test where this setting is set is a convention of the Flex skeleton (and of symfony-standard before that), but it is not a requirement of Symfony at all (you could name it however you want)

btw, we can even check which message should be used, as we can check whether browser-kit is installed (using class_exists(Client::class) on the browserkit client)

@SerkanYildiz if I can I would gladly contribute in any way I can! If you'll allow me I'd gladly work ona fix for this and create a merge request.
You assumption regarding Docker could be correct, we are using Docker indeed.

Hi @mehlichmeyer,

I already created a PR (#30479) to fix this issue.

I would like to add a small hint for others who might also come here after getting this error, because it was not clear what the real problem was at the beginning.

I get this message after I upgraded my project from Symfony 4.4 to 5.2. In case you use phpunit/phpunit (with symfony/browser-kit and symfony/css-selector) as well as rely on APP_ENV in .env and phpunit.xml, for instance:

<env name="APP_ENV" value="test"/>

Running PHPUnit with tests using static::createClient triggers the error message (You cannot create the client used in functional tests if the "framework.test" config is not set to true.), because it still thinks you are using APP_ENV=dev (or whatever your default is). Also framework.test was true in (config/packages/test/framework.yml).

Solution

You have to force APP_ENV to be set to test, e.g. by using the following in your phpunit.xml:

<env name="APP_ENV" value="testing" force="true"/>

Source: https://stackoverflow.com/a/53832084/5301527

If you want a prod env, you need to config/packages/framework.yaml add:

when@prod:
    framework:
        test: true
        session:
            storage_factory_id: session.storage.factory.mock_file

and into phpunit.xml.dist add APP_ENV = prod:

<?xml version="1.0" encoding="UTF-8"?>

<!-- https://phpunit.readthedocs.io/en/latest/configuration.html -->
<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="vendor/bin/.phpunit/phpunit.xsd"
         backupGlobals="false"
         colors="true"
         bootstrap="tests/bootstrap.php"
         convertDeprecationsToExceptions="false"
>
    <php>
        <server name="APP_ENV" value="prod" force="true" />
        ...
    </php>